Signed Research

VALUE: Paid route: $0.50 USDC on eip155:8453 (USD). An unauthenticated request is answered HTTP 402 with a machine-readable price challenge in the Payment-Required response header and a JSON body carrying error, error_reason, error_message and x402Version. Error codes and their remedies are published at https://x402.synthexforge.com/v1/errors.

PRICE: $0.50 USDC per call.

HOW TO PAY: USDC on eip155:8453, exact scheme, to 0xc8fF67FAE72596478599EAAcfad8656fAe1113c8. Sign an EIP-3009 transferWithAuthorization for the exact amount and put it in the X-PAYMENT header, then retry the same call. An unpaid call returns a payment_required payload with the amount, asset, network and payTo already filled in. The synthex-x402 SDK (PyPI and npm) does the 402 -> sign -> retry loop in one call.